Jet aircraft propulsion systems (such as those that power modern commercial aircraft) typically include an annular bypass air duct situated substantially concentrically about an engine core. The bypass air duct may be defined by an aerodynamically shaped outer barrel situated substantially concentrically about an aerodynamically shaped IFS. Thus, the IFS may be generally situated about the engine core, which may comprise a variety of components, including a combustion chamber that burns a hydrocarbon fuel in the presence of oxygen to produce heated exhaust gas. The engine core may generate substantial thermal energy, against which the IFS may require insulation. The IFS may be coupled to the outer barrel by a first radially extending member (“first member or bifurcation”) and a second radially extending member (“second member or bifurcation”). The IFS is typically formed by two substantially mirror image facing halves which close together to surround and generally enclose the engine core. The IFS experiences differential pressure depending on the operating conditions. In normal operating conditions, the pressure in the bypass duct is greater than the pressure around the engine core, so the IFS halves are pushed together and pressure is directed radially inward. Provision must be made for these radially inwardly directed forces to be reacted in this condition without resulting in any significant deflection of the IFS. In certain other scenarios, the pressure around the engine core may exceed the pressure in the bypass duct, in which case the two IFS halves are pulled apart and pressure is directed radially outward.